/Engine/Source/Runtime/Core/Public/Internationalization/InternationalizationManifest.h
Adds a manifest entry.
Returns true if add was successful or a matching entry already exists, false is only returned in the case where a duplicate context was found with different text.
bool AddSource ( const [FLocKey](API\Runtime\Core\Internationalization\FLocKey) & Namespace, const [FLocItem](API\Runtime\Core\Internationalization\FLocItem) & Source, const [FManifestContext](API\Runtime\Core\Internationalization\FManifestContext) & Context )